1. Field of the Invention
This invention relates to an apparatus for adjusting the mutual distances of several movable elements placed side by side, particularly pairs of blades for straight-line cutting of sheet material. More particularly, this invention relates to an apparatus for adjusting and maintaining the mutual distances of several movable elements placed side by side such that following a cutting operation or other movement of the blades during transposition, the movable elements are moved at fixed relative distances such that the distance between successive movable elements is maintained. The invention also relates to a control device of the type described including means for repositioning the movable elements such that during repositioning the position of subsequent movable elements is adjusted by determining the extent to which a first movable element is moved from a fixed stop position. Stated differently, during a repositioning operation, the apparatus measures the extent to which a first movable element is moved from a fixed movable position. The apparatus then moves a second or downstream movable element the same distance by which the first movable element was moved. Subsequent movable elements are moved in response the same distance by which the first movable element is moved from the fixed stop position to its new position.
The invention is particularly directed to apparatuses of the type described provided with a feeler-controlled driving mechanism for each movable element and a control unit with which the new position of a movable element associated therewith can be adjusted. The feeler-controlled driving mechanisms feed the control impulses to the associated driving mechanism until the associated elements reaches the new position desired. This will be explained in greater detail below.
2. Discussion of the Prior Art
It has long been known to provide apparatuses which attempt to control the relative position of movable elements. With a known apparatus of this type, the control of the driving mechanism by which the elements are moved takes place in such a manner that signals generated by the action of a feeler feed an actual value into a control unit which is checked with a desired value. As long as there is a desired-actual value difference, the element is activated by the driving mechanism. In other words, the adjustment of the relative position is done by comparing the actual distance between movable elements with the desired distance. A signal is generated and at least one of the elements is moved until the apparatus detects no difference between the actual distance between the movable elements and the desired distance. Obviously, at such a point no adjustment in the relative position of the movable elements is required. Unfortunately, such an apparatus requires complex controls and requires means to compare a desired value with an actual value. Stated differently, various factors must be determined, to wit, the desired value and the actual value, and these must be compared. A signal must be generated as a result of the comparison which will actuated a driving mechanism. All of this is considered to be inordinately complex.
It therefore became desirable to provide an apparatus of this type by which the transposition or repositioning of the individual elements could take place without requiring such a comparison merely by measuring the extent to which a first movable element is moved and adjusting the other elements in response to such measurement. These and other objects are provided by the within invention as described below.